Going on a climate change march on your 10th wedding anniversary, now that's what I call dedication. Good old Piers & Lisa - we always knew they were perfect. And they seemed genuinely re-inspired by the huge march and excellent speeches, too.

George Monbiot made the most frightening point: that we (humans) have till 2030 to cut carbon emissions by 90%. If we don't, the world will warm by more than 2 degrees, trigger runaway warming and become mainly uninhabitable for human life.

I was filming from the stage and getting some cutaways of the crowd. Started a shot of a dodgy looking bloke in a big Russian hat, who was filming on his mobile phone and took all of 30 seconds to realise it was... my dad. Had no idea he was here let alone filming the same thing as me. I teased him about the size of his camera and he fired back with: "And when's your film going to be finished? Mine will be available tonight." Ha ha.

Lizzie and I were trying out our new gadget - a glidecam. Like a steadicam, but for poor film crews. It's a gyroscope-type thing which the camera sits on and is counterbalanced with lots of weights, so when you walk the camera doesn't bounce up and down and the shot looks like it's floating along. When you first pick it up it feels quite heavy. Once you get to the end of carrying it for eight hours on a six-mile protest across London, your forearms are so wasted that Lizzie has to hold the menu and you have to drink soup with a straw as you can't pick up a spoon.